sylwester@sylwester-pc:~$ xrandr --addmode HDMI-0 "1368x768_60.00"
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  18 (RRAddOutputMode)
  Serial number of failed request:  29
  Current serial number in output stream:  30
sylwester@sylwester-pc:~$